The present invention relates to a semiconductor device, and a manufacturing method thereof, and is applicable to, for example, manufacturing of a semiconductor device having a low breakdown voltage transistor and a high breakdown voltage transistor.
As one of nonvolatile storage elements, a single gate type MONOS (Metal Oxide Nitride Oxide Semiconductor) memory including source/drain regions formed at the surface of a semiconductor substrate, a memory gate electrode, and a charge accumulation film formed between the semiconductor substrate and the memory gate electrode is known. For a nonvolatile storage device, such MONOS memories are arranged in an array to form a memory array. Selection of the MONOS memory at a read operation, or the like can be performed, for example, using a selection transistor coupled in series with each MONOS memory.
Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-48710) describes that a single gate type MONOS memory, a low breakdown voltage MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and a high breakdown voltage MOSFET are merged over the same substrate.
Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2007-243095) describes that in a split gate type MONOS memory including mutually adjacent control gate electrode and memory gate electrode, the end of an ONO (Oxide Nitride Oxide) film under the memory gate electrode is prevented from being retreated.